1. Field of the Invention
The present invention relates to a control system for controlling a throttle valve for intake air by detecting the angle of depression of an accelerator pedal (accelerator pedal angle) by a sensor.
2. Description of the Related Art
In a prior-art control system a potentiometer or similar device is used to detect the depression of the accelerator pedal. The potentiometer, however, is likely to produce noise and instantly produces a large change in output if the potentiometer is deteriorated.
There has been in use such an example provided with both a potentiometer and a potentiometer switch for detection of sensor abnormality by comparing their outputs.
This type of prior-art control system, however, is disadvantageous as a motor vehicle will fail in running in the event that the output values of the potentiometer and the potentiometer switch do not agree.
Furthermore it has such a problem that no abnormality can be detected in the whole range of angle of accelerator pedal depression.